DE 31 15 840 A1 discloses that with resistance welding, wherein, during the welding, the electric resistance between two welding electrodes is automatically adjusted through a change of the contact force of the electrodes in a reference resistance curve, and in addition, the electric potential at the welding electrodes is adjusted to a reference potential curve.
EP 1 508 396 B1 discloses a welding robot, comprising an industrial robot and a welding tongs, which is attached to the robot arm of the industrial robot. The welding tongs, which can be moved by means of the robot arm, comprises two electrode arms, an electric motor for moving the electrode arms, and force sensors for determining the contact force applied by the electrode arm. The welding device further comprises a regulating device, which is configured, due to the deviation of the actual contact force from the target contact force, to generate a correction variable for the motor position of the electric motor.